Search the local db to find the local DN using the original DN as search key.
This way we do not have to rely on weak and faulty heuristicts based on DN
names.
Add a few helper functions in the process and change the way we pass members to
sysdb_store_group_send(), instead of passing users and groups list, just add
member DNs to the other sysdb attrs.

This allows for correctly reporting nested group members, while at the same
time not paying a too high price for caluclating nested groups at runtime e
very time a search is made.

This brings down the time needed to enumerate my group database
from 2.4 seconds to 0.15 seconds.

- save current ccache file to sysdb
- use the saved ccache file if the user has running processes
- create an empty ccache if offline
- return enviroment variables if offline

In building the DN string we weren't correctly escaping the value of the RDN
component. This patches fixes that.

After completing an upgrade successfully, we were still falling
into the "version not found" case. We should be exiting the
function after performing the upgrade.